Tube coupling

ABSTRACT

Couplings and coupling components which prevent relative rotation between tubular members when break away torque forces are applied to the tubular members. In one embodiment, the invention is a locking ring for preventing relative axial rotation between two generally tubular members. The ring is shaped to receive a sealing gasket and has two side faces wherein each side face is shaped to frictionally engage one of the tubular members to thereby prevent relative axial rotation between the tubular members. The invention is also directed to a coupling including a locking ring and a method of making a coupling having a locking ring to prevent relative rotation between the tubular members. In another preferred embodiment, the invention is a coupling comprising two generally tubular members each having a sealing end face, a raised, annular sealing bead, an inner bore, and a frictional surface located radially outward of the sealing bead. The tubular members are generally coaxially arranged such that the sealing faces face each other. The coupling further comprises a sealing gasket captured between the sealing beads for sealing the coupling, wherein the frictional surfaces engage the sealing gasket to prevent relative rotation between the tubular members.

This application claims priority to U.S. provisional application Ser.No. 60/048,931, filed Jun. 16, 1997, and to U.S. provisional applicationSerial No. 60/089,127, filed Jun. 11, 1998, Express Mail Label No.ELO85314975US.

FIELD OF THE INVENTION

The present invention is directed to tube couplings, and moreparticularly, to tube couplings and coupling elements which preventrelative rotation between tubular coupling members.

BACKGROUND OF THE INVENTION

Tube couplings of the type in the present invention are generally shownand described in U.S. Pat. Nos. 3,521,910 and 5,145,219, hereinincorporated herein by reference. Those patents describe tube couplingswherein first and second tubular members having central through passagesand sealing end faces with annular, raised beads are arranged tosealingly engage on opposite sides of an annular metal gasket. Suitablethreaded nut members are then rotated to drive the tubular memberstoward each other to cause the beads to sealingly engage the gasket.

U.S. Pat. No. 5,145,219 proposes modifications and/or additionalcomponents to reduce or eliminate undesired relative movement betweenthe tubular members and between the tubular members and the gaskets. The'219 patent is primarily directed to preventing such relative rotationdue to transmitted torque forces. Transmitted torque is the rotationalforce applied to the tubular members during make up of the fitting. Insome situations it may be desired to accommodate “break away” torque,which is a much stronger rotational force applied to the coupling afterit is made up. Break away torques may be imparted upon the system byenvironmental forces, as well as rough handling by operators. When theimparted forces are sufficient so as to cause one coupling member to“break away” and rotate relative the other coupling member, or relativethe sealing gasket, the gasket may be scored. Accordingly, there existsa need for a tube coupling which can prevent relative rotation betweentubular members when break away torque forces are applied.

SUMMARY OF THE INVENTION

The present invention resides in various coupling and couplingcomponents which prevent relative rotation between tubular members whenbreak away torque forces are applied to the tubular members. In oneembodiment, the invention is a locking ring for preventing relativeaxial rotation between two generally tubular members. The ring is shapedto receive a sealing gasket and has two side faces wherein each sideface is shaped to frictionally engage one of the tubular members tothereby prevent relative axial rotation between the tubular members. Theinvention also includes a coupling incorporating the locking ring, and amethod of making a coupling having a locking ring to prevent relativerotation between the tubular members.

In another preferred embodiment, the invention is a coupling comprisingtwo generally tubular members each having a sealing end face, a raised,annular sealing bead, an inner bore, and a frictional surface locatedradially outward of the sealing bead. The tubular members are generallycoaxially arranged such that the sealing faces face each other. Thecoupling further comprises a sealing gasket captured between the sealingbeads for sealing the coupling, wherein the frictional surfaces engagethe sealing gasket to prevent relative rotation between the tubularmembers.

Various other embodiments of the invention are described and claimedherein, and other features and advantages of the present device willbecome apparent from the following detailed description, with referenceto the accompanying drawings and claims, which form a part of thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of the tube couplingof the present invention;

FIG. 2 is a perspective view of one of the tubular members of thecoupling of FIG. 1;

FIG. 3 is an exploded perspective view showing an alternate embodimentof the invention;

FIG. 4 is an exploded perspective view showing another embodiment of theinvention;

FIG. 5 is an exploded perspective view showing another embodiment of theinvention;

FIG. 6 is a cross-sectional view showing yet another embodiment of thepresent invention;

FIG. 7 is an exploded cross-sectional view of another alternateembodiment of the present invention;

FIG. 8 is a front view taken on line 8—8 of FIG. 7 showing in moredetail the lock ring and gasket assembly;

FIG. 8A is a front view of an alternate embodiment of the locking ringthat may be used in the coupling of FIG. 7;

FIG. 8B is a front view of another alternate embodiment locking ringthat may be used in the coupling of FIG. 7;

FIG. 9 is a cross-sectional view showing another embodiment of the tubecoupling of the present invention;

FIG. 10 is partial cross-sectional view showing another embodiment ofthe present invention;

FIG. 11 is partial cross-sectional view showing another embodiment ofthe present invention;

FIG. 12 is a partial cross-sectional view showing another embodiment ofthe present invention; and

FIG. 13 is partial cross-sectional view showing yet another embodimentof the present invention.

DETAILED DESCRIPTION

As shown in FIGS. 1 and 2, in one embodiment of the invention thecoupling includes a pair of opposed generally tubular members 10, 12,each having a central axial cylindrical bore 11, 13. The tubular members10 and 12 are shown as being identical but, as one skilled in the artwill quickly recognize, they could differ from one another in a varietyof particulars as shown and discussed in the above-mentioned patents.Each of the members 10, 12 have sealing end faces 15, 17 that include asealing bead 14 that extends coaxially about the associated bore 11, 13.An annular metal gasket 16 is positioned between the end faces 15, 17.The sealing beads 14 of each member 10, 12 may be driven into sealingengagement with the opposite side faces 20 of the gasket 16 bycooperating male and female threaded nuts 18 and 19. In this manner, thebeads 14 engage the gasket 16 to seal the coupling.

For clarity, the male and female threaded nuts 18 and 19 are omittedfrom the other Figures in this application, it being understood that acomplete coupling assembly includes the male and female nuts 18, 19.

The end faces 15, 17 are provided with frictional surfaces 22 to preventrelative rotation between the members 10, 12 and between the tubularmembers 10, 12 and the gasket 16. The frictional surfaces 22 lieradially outwardly of the respective sealing beads 14, and engage thegenerally smooth gasket 16. In the illustrated embodiment, the roughenedareas or frictional surfaces 22 are formed by bands of knurling thatextend axially forwardly a distance only slightly less than the axialheight of the associated bead 14. The dimensions of the knurling allowthe frictional surface 22 to positively engage the gasket 16 when thebead 14 is sealingly engaged into the gasket. Whether the knurlingextends axially outwardly beyond the associated bead 14 is not, however,critical. The engagement between the knurls and the gasket must besufficient to ensure that any applied torque on one tubular member istransmitted through the gasket and to the other tubular member.Furthermore, the frictional surfaces 22 may be of nearly any form solong as there is sufficient frictional engagement between the surfaces22 and the gasket 14. The surface may include various forms ofroughening, protrusions, knurling and the like, without departing fromthe scope of the invention.

It is to be understood that the term “frictional engagement” shallinclude any means of treating a surface such that the force required toproduce relative rotation between the treated surface or surfaces isincreased over the force required for a smooth, untreated surface. Theterm encompasses roughening, knurling, raised protrusions and the like,even though some of these treatments may not increase the force requiredto produce relative rotation strictly through the increase of frictionalforces. For example, knurling may produce the desired results byembedding the raised knurls into the opposite surface, but this is stillto be considered increasing the “frictional engagement” for the purposesof this application.

FIG. 3 shows an alternate embodiment which is arranged so as to reducethe relative rotation between the tubular members or the tubular membersand the gasket. In this embodiment, each of the tubular members 10, 12include end portions 21, 23 having a non-circular outer periphery, inthis case, a hex configuration. In the illustrated embodiment, the endportions 21, 23 are located radially outwardly of the respective sealingend face 15, 17. The beads 14 are, of course, arranged to engage onopposite sides of the gasket member 16 when driven thereinto bycooperating threaded body portions (not shown). In the FIG. 3embodiment, the end portions 21, 23 are identical in exterior shape andconfiguration. During make-up of the fitting, the end faces 15, 17 arepositioned in axial alignment with the hex configurationscorrespondingly aligned. A somewhat U-shaped rigid frame member 30 isthen moved transversely into engagement with the surfaces of the hexconfiguration to hold the members 10 and 12 against relative rotation.The member 30 is held in place on the end portions 21, 23 and totallyenclosed by the threaded body members after make-up is completed. Itshould be understood that nearly any non-circular shape end portions 21,23 may be used, and nearly any shape or configuration frame member maybe used, so long as the frame member 30 can receive the non-circular endportions 21, 23 so as to prevent relative rotation therebetween.

FIG. 4 shows yet another embodiment wherein the sealing end faces 15, 17have raised protrusions, such as axially extending pins 34, locatedradially outwardly of the sealing bead 14 to engaged the gasket. Thepins 34 may extend any suitable distance to engage the opposite sidefaces 20 of the gasket 16. In one embodiment, the pins 34 extendoutwardly a distance slightly greater than the total height of the beads14. Here, again, the threaded coupling body portions (not shown) act todrive the pins 34 into direct positive penetrating engagement with thegasket 16. Thus, relative rotation between the tubular members isprevented. In a preferred embodiment, the pins are equally radiallyspaced.

A still further possible embodiment is shown in FIG. 5. In FIG. 5, thesealing portions of the tubular members 10, 12 and the gasket 16 areenclosed by a pair of cup-shaped members 38 each having a base 39 and alip portion 41. Each lip portion 41 is shaped to frictionally engage theother lip portion. In the illustrated embodiment the lip portions 41include teeth 40 shaped to engage the teeth 40 of the other cup-shapedmember 38. Each cup-shaped member 38 includes an opening 42 in the base39 to receive a non-circular portion 46 of the shaft portion 45 of therespective tubular members 10, 12. The openings 42 are provided with atleast one flat portion 44 that is arranged to positively engage with acorresponding non-circular portion, or flat 46, formed on the respectivetubular member. The interengaging teeth 40 between the two cup members38 prevent relative rotation between the cup members 38 and theirrespective tubular members.

In the embodiment illustrated in FIG. 6, the end faces 15, 17 of thetubular members 10, 12 are provided with interengaging elements in theform of a generally radially extending groove 50 formed in end face 15and a generally radially extending flange 52 formed in the end face 17.The groove 50 may include a taper into which a tapered end portion 53 ofthe flange is received. The dimensioning of the groove and flange issuch that a wedging and binding takes place between the groove 50 andthe flange 52 when proper sealing engagement is achieved between thesealing beads 14 and the sealing gasket 16. Two or more sets ofinterengaging flanges and grooves may be used. Here, again, it should beappreciated that the threaded coupling body portions are not shown.

FIG. 7 shows an exploded longitudinal cross-sectional view of a furtherarrangement wherein relative rotation between the tubular members 10 and12 is prevented when the fitting is made up. In this embodiment, a lockring 60 formed of a material harder than the tubular members ispositioned between the end faces 15, 17. The lock ring 60 receives thegasket 16 therein, and has an inner diameter sized to receive the gasket16 by an interference fit. In one embodiment, the lock ring 60 may besplit so that it is radially resilient to grip the gasket 16.Furthermore, a groove could be placed in the inner diameter of the lockring 60 so as to receive the gasket 16. The ring 60 is preferably harderthan the end faces 15, 17 of the tubular members, and may be made ofstainless steel.

The ring 60 is shaped to frictionally engage the tubular members 10, 12.In one embodiment, the locking ring has a substantially smooth surfaceon its side faces 63, as even a smooth side face may provide enoughfriction to reduce relative rotation between the tubular members. Inorder to increase the frictional engagement, one or more protrusions maybe formed on the side faces 63 of the locking ring 60. As shown in FIG.8, the protrusions may comprise knurls, or raised ridges, extendinggenerally radially on the side face 63. When the coupling is assembled,the protrusions are located radially outwardly of the gasket 16 and thebeads 14.

Alternate embodiments for increasing the frictional engagement of thelocking ring 60 are illustrated in FIGS. 8A and 8B. FIG. 8A shows alocking ring 60 having a plurality of radially-extending grooves 67formed in the side faces 63. The grooves may be formed on both sides ofthe ring 60, and are preferably equally radially spaced. The side wallsof each groove form a radially-extending edge which digs into therespective end face 15, 17 during make-up to thereby frictionally engagethe end face. FIG. 8B shows an embodiment of the locking ring of thepresent invention wherein the grooves 65 form an angle with a radiallyextending line. This arrangement gives each groove 65 a longer edge toimprove the frictionally engagement. In yet another embodiment (notillustrated) each side face 63 may be machine roughened so as to formrelatively shallow grooves which improve frictional engagement.

As shown in FIG. 7, the opposite side faces 63 of the lock ring arepreferably slightly tapered, although the side faces 63 may not betapered. If a taper is utilized, the taper may be of any suitable angle,and in one preferred embodiment is about 10°. As shown in FIG. 7, theside faces 63 are oppositely inclined with respect to a radial planesuch that the width of the ring decreases in the radially outwarddirection. In this configuration, the inner diameter of the ring extendsforwardly to form an edge which digs into the end faces 15, 17, tofrictionally engage the tubular members 10, 12. The dimensions of thelock ring may be such that as the tubular members 10 and 12 are broughttogether into the made up position, sealing engagement of the gasket 16with the sealing beads 14 takes place substantially simultaneously withengagement of the hardened lock ring 60 with the end faces of thetubular members. Thus, when made up, the lock ring is firmly engagedinto the tubular members 10, 12 preventing relative rotationtherebetween. However, the coupling may be arranged such that theengagement of the gasket with the sealing beads takes place before, orafter, the engagement of the locking ring with the end faces of thetubular members. After make up, the gasket is compressed between thesealing beads to seal the coupling, and the lock ring is preferablyembedded in the end faces 15, 17.

Yet another form of the invention is shown in FIGS. 9-11. As best seenin FIG. 9, wherein only tubular member 10 is shown, there is a splitouter ring or sleeve 64 which carries a pair of small locking rings 66that are formed from a material harder than the tubular members 10 and12. The locking rings 66 each have a pair of side faces 73, and arelocated radially outward of the beads 14. The locking rings areassembled in the manner shown by snapping the outer sleeve 64 open andsliding the lock rings 66 in together with an associated gasket 16. Thelocking rings 66 are located on either side of the gasket 16, and uponmake up engage the gasket 16 and associated end faces 15, 17, throughroughening, knurling, or forming protrusions on the side faces 73 and/orthe end faces 15, 17. Alternately, the side faces 73 and/or the endfaces 15, 17 may be smooth, as the smooth surface-to-surface contact mayprovide enough force to lock the entire assembly together.

The outer sleeve 64 provides a method for pre-mounting the assembly toone or the other of the tubular member members. When the assembly ismade up, the small lock rings 66 engage the opposite side face 20 of thegasket 16, and also engage the end faces 15, 17 of the tubular membermembers 10 and 12. This provides a direct lock through the assembly sothat one tubular member cannot rotate relative to the other. Either theside faces 73 of the locking rings, or end faces 15, 17 of the tubularmembers 10, 12 may be shaped to improve the frictional engagementtherebetween through any of the methods discussed above.

FIG. 10 shows a slightly modified form of the embodiment of FIG. 9. Inthis modification, the outer sleeve member 64 which holds the lock rings66 in place is formed from a metal stamping in which the gasket and lockrings are held between deformations, or swages, 68 and 69 that extendradially inward. In this embodiment, the outer ring can be a split ringwhich is deflected radially outward to allow the lock rings and gasket16 to be inserted, or it can be a solid ring which has a deformation 68or 69 swaged over after the gasket 16 and lock rings 66 have beenassembled therein. A similar arrangement is shown in FIG. 11. In thisembodiment, as well as the FIG. 10 embodiment, the extension of thesleeve 64 allows it to be pre-mounted on the tubular member duringassembly of the entire fitting. In this modification, the outer sleevemember 64 is radially deformed outwardly to provide a suitable groove 75for closely receiving the lock rings 66 and the gasket 16 in theposition shown. Here, again, the outer sleeve member 64 can be split sothat it can be radially deflected to load the lock rings and gasket inplace, or it can have one or the other ends swaged inwardly after thelock rings and gaskets have been placed therein.

A further form of the invention is shown in FIG. 12. In this embodiment,a combined lock ring and housing member, or retainer, 70 retains thesealing gasket 16 and a locking ring 74 in place. The retainer 70 has aninwardly extending portion 72 that is knurled or grooved on both sidesso as to provide gripping teeth for engaging the end face 15 of theassociated tubular member 10 and the side face 20 of the gasket 16.Again, nearly any means for improving the frictional engagementstherebetween may be used, as discussed in greater detail above.Associated with this assembly is a separate lock ring 74 which isreceived in the assembly as shown and held therein by swaged-inprotuberance 76 of the retainer 70, or by making the entire member 70 asa split ring so it can be sprung open to receive gasket 16 and lock ring74. When the assembly of FIG. 12 is mounted in position between thetubular members and the tubular members are tightened to their sealingposition, the gasket and their associated end face of the tubularmembers 10 and 12 are engaged, thereby providing a direct lock betweenthe two tubular members 10, 12 to prevent relative movementtherebetween.

A final, and much simpler, arrangement is shown in FIG. 13. In thisembodiment, a single, continuous, relatively rigid and hard ring orsleeve 78 is located about the outer surface 81, 83 of the tubularmembers 10, 12. The inner diameter of the sleeve is preferably slightlysmaller than the outer diameters of the end faces 15, 17. The innersurface of the sleeve 78 preferably has a plurality of axially-extendinggrooves or sharp edged ribs 80. During make up of the assembly, the ribs80 are driven into place to grip the outer peripheral surfaces of themembers 10 and 12 to prevent subsequent relative rotation of thecomponents relative to one another.

The preferred form of the present invention has been described above.However, with the present disclosure in mind it is believed that obviousalterations to the preferred embodiments, to achieve comparable featuresand advantages, will become apparent to those of ordinary skill in theart.

What is claimed is:
 1. A locking ring and metal annular sealing gasketassembly for preventing relative axial rotation between two generallytubular members, said ring being shaped to receive the sealing gasket;said locking ring being metal and having two side faces wherein eachside face includes a knurled surface to frictionally engage a respectiveone of said tubular members to thereby prevent relative axial rotationbetween said tubular members; said sealing gasket being retained withina central portion of said locking ring; said side faces being inclinedwith respect to a radial plane and oppositely inclined such that thewidth of said ring decreases in the radially outward direction.
 2. Theassembly of claim 1 wherein said locking ring has an inner diametersized to receive said sealing gasket by an interference fit.
 3. Theassembly of claim 1 wherein each side face has one or more protrusionsextending forwardly of each respective side face, each of said one ormore protrusions being shaped to frictionally engage one of said tubularmembers.
 4. The assembly of claim 3 wherein at said one or moreprotrusions comprise one or more raised ridges.
 5. The assembly of claim4 wherein said one or more raised ridges each extend generally radially.6. The assembly of claim 1 wherein one of said side faces has a grooveformed therein.
 7. The assembly of claim 6 wherein said groove extendsgenerally radially.
 8. The assembly of claim 6 wherein said groove formsa pair of generally radially-extending edges.
 9. The assembly of claim 6wherein said groove forms an angle with a radially-extending line. 10.The assembly of claim 6 wherein the other of said side faces has agroove formed therein.
 11. The assembly of claim 1 wherein each sideface has at least two radially extending grooves formed therein, andwherein said grooves are equally radially spaced.
 12. The assembly ofclaim 1 wherein said ring is of harder material than said tubularmembers.
 13. The assembly of claim 1 wherein said ring is stainlesssteel.
 14. The assembly of claim 1 wherein said inclination is 10degrees.
 15. A tube coupling comprising: two generally tubular metalmembers each having a sealing end face and an inner bore, said tubularmetal members being generally coaxially arranged with each other afterthe coupling is assembled; a metal locking ring that prevents relativerotation between said sealing end faces, said ring having two sidefaces, each side face having a surface to frictionally engage arespective one of said tubular members sealing end faces; and a metalsealing gasket received in said locking ring for sealing said coupling;wherein said side faces are inclined with respect to a radial plane;wherein each tubular member has a bead on its respective sealing face,each bead extending around its respective inner bore and wherein saidsealing gasket is compressed between said beads to seal the coupling.16. The coupling of claim 15 wherein each side face has one or moreprotrusions extending forwardly of each respective side face, each ofsaid one or more protrusions being shaped to frictionally engage one ofsaid tubular members.
 17. The coupling of claim 16 wherein each of saidone or more protrusions is embedded in its respective sealing face. 18.The coupling of claim 16 wherein said one or more protrusions are shapedand sized to engage each respective tubular member as said gasketengages said beads during make-up.
 19. The coupling of claim 16 whereinsaid one or more protrusions are located radially outwardly of saidgasket and said beads.
 20. The coupling of claim 16 wherein said one ormore protrusions comprise knurling on each side face.
 21. The couplingof claim 15 wherein each side face has a groove formed therein.
 22. Thecoupling of claim 15 further comprising a pair of coupling nuts fordriving said sealing faces toward each other.
 23. The coupling of claim18 wherein said ring is of harder material than said sealing end faces.